相关疑难解决方法(0)

我有以下代码来显示没有箭头的popoverview(对话框),它工作正常.唯一的问题是,对话框显示在左上角(IPad).我想将视图置于屏幕中心.

在我的下面的代码中要更改或添加什么？:

func show_help(){


    let storyboard = UIStoryboard(name: "Main", bundle: nil)
    let controller = storyboard.instantiateViewControllerWithIdentifier("Help") as! UIViewController

    controller.modalPresentationStyle = UIModalPresentationStyle.popover

    let popoverPresentationController = controller.popoverPresentationController

    // result is an optional (but should not be nil if modalPresentationStyle is popover)
    if let _popoverPresentationController = popoverPresentationController {

        // set the view from which to pop up
        _popoverPresentationController.sourceView = self.view;
        _popoverPresentationController.permittedArrowDirections = UIPopoverArrowDirection.allZeros;
        // present (id iPhone it is a modal automatic full screen)
        self.presentViewController(controller, animated: true, completion: nil)
    }

}

额外的信息

在我的视图中,链接到我的viewcontroller我设置了这样的优先大小:

override …